Sewing-machine.



SEWING MAGHINE. APPLICATION men SEPT. 19. 1914.

Patented Aug. 17, 1915.

resident of Belvidere,

nan sate smear @FFELQE.

RICHARD K. Horns/mun, or Bsnvrnnnn, ILLINOIS.

SEWING-MACHINE.

Specification of Letters Patent.

Patented Aug. 1'7, 1915..

Application filed September 19, 1914. Serial No. 862,588.

To all whom it may concern:

Be it known that I, RICHARD K. Horr- MANN, a citizen of theUnited States, and Boone county, State of Illinois, have invented certain new and useful Improvements in Sewing-Machines, of which the following is a specification.

This invention relates to sewing machines the thread irrespective of the size of the thread or the amount of thread on the bobbin.

The novel features of the invention will be apparent from the following description taken in connection with theaccompanying drawings in which? Figure l'is a side elevation of a rotary shuttle embodying my invention; Fig. 2 is a section on line 22 of Fig. l, with the bobbin and tension device shown in elevation; Fig. 3 is a view similar to Fig. l and showing certain parts in a different arrangement, and Fig. 4 is a perspective view of the tension device.

Referring to the drawings 10 indicates the shuttle which is provided with a central post 11 for the bobbin 12. The shuttle has inwardly projecting lugs 13 and 14 in which a pivot pin 15 is journaled. Secured to the pin 15 is an arm 16 arranged on the side of the shuttle and adapted to swing to and from a position over the bobbin. As shown in Fig. 1 the arm 16 is in position to hold the bobbin in the shuttle and when in this position the beveled end 17 of the arm engages the under surface of a lug 18 on the outer end of the post 11. A leaf spring 19 is secured on the under side of the arm 16 and when the arm is in the position shown in Fig. 1 ,this spring holds the arm in engagement with the lug 18. When the arm 16 is swung to the position shown in Fig. 3 the bobbin 12 may be removed from the shuttle, the arm being held in this position by the engagement of the lateral extension 20 of the spring 19 with a recess 21 in the shut tle. The spring 19 is also provided with a.

of the leaf 23 on the lateral extension 22 which serves as a thumb piece to permit the spring to be disengaged from the recess 20.

A tension leaf 23 is provided with a pair of ears 21 which are journaled on the pivot 15 so that the leaf 23 may be swung on the .pivot independently of the arm 16. A

spring 25, coiled about the pivot 15, has the end 26 thereof in engagement with the inner surface of the shuttle, the end 27 bearing against the leaf 23 and normally pressing the leaf against the' thread on the bobbin The thread from the bobbin 12 leads through an o ening 28 in the shuttle and the pressure of tie leaf 23 on the thread produces a uniform tension therein irrespective of the size of the thread or of thread on the bobbin. It will be readily the amount understood that when the bobbin is full of thread it will unwind much easier than when nearly empty because of the longer moment-arm when the bobbin is full. The spring 25 is so arranged that the pressure thread is a maximum when the bobbin is full and therefore as the thread is withdrawn from the bobbin the pressure of the plate on the thread decreases.

In other words, the pressure of the leaf 23 on the thread varies directly with the amount of thread on the bobbin and thus compensates for the variation in tension due to the decrease in the moment arm, as the bobbin is emptied.

Vhen it is desired to remove the bobbin from the shuttle it is essential to swing the plate 23 from between the flanges of the bobbin and in order to conveniently effect this a pin or arm 29 is secured to the 15 and arranged to engage'the leaf 23 and cause the latter to be swung away from the thread as the arm 16 is swung to the position shown in Fig. 3. When the leaf is thus swung from its operative position by the arm 16 the latter is under theinfluence of the spring 25 whichtends to swing it back to the position shown in Fig. 1. The engagement of the eXtension 20 with the recess 21, however, holds the arm 16 against the pressure of the spring 25. Y

When the machine is running at high speed there is normally a tendency for the large bobbin to overrun or unwind too much thread and the leaf 23, bearing on the thread, acts as a brake to prevent this.

pivot Having thus described my invention, what I claim is 1. The combination with a shuttle, of a pivoted tension leaf adapted to contactwith the thread on the bobbin and a helical torsion spring coaxial with the pivot of said leaf and having one end engaging the shuttle and the other end engaging the leaf and so arranged that the pressure of the leaf on the thread will vary directly with the distance of the leaf from the axis of the bobbin.

2. The combination with a shuttle, of a bobbin, a pivot, an arm secured to said pivot and adapted to hold said bobbin in position,

a spring-pressed leaf loosely arranged on a said pivot andadapted to engage the thread on said b0bbin,-a&1d means on said pivot adapted to engage said leaf and withdraw the same from the thread when said'arm is swung to release said bobbin. 4

3. The combination with.a shuttle, of a bobbin, a pivot, an arm secured to said pivot and adapted to hold said bobbin in position, a springpressed leaf adapted to engage the thread on said bobbin, means whereby said leaf is withdrawn from operative position when said arm is moved to releasesaid bobs bin, and a springon said arm adapted tov engage said shuttle to hold said arm andleaf in inoperative positions.

In testimony whereof I affix my signaturein presence of two Witnesses.

RICHARD K. HOHMANN.

Witnesses 4 FRANK SEWELL, v CHAS. TL SEWELL. 

